Pioneer PDP-V401 Field Service Manual page 10

PDP-V402
ADJUSTMENTS OF PARTS
Procedure Adjustment
1 Blanking pulse width
adjustment (CBLK)
2 VCO control voltage
adjustment
Vertical sync
freerunning
3
frequency
adjustment
V , V , V
ADR SUS OFS
voltage adjustment
4
146
Input Signal Adjusting Point
VR2802 (VBLK)
100% white signal
VR2803 (HBLK)
(ANALOG VIDEO
ASSY)
No-input
L7650
(NO SYNC
(CONTROL
displayed on screen)
ASSY)
No-input
VR7650
(NO SYNC
(CONTROL
displayed on screen)
ASSY)
VR3301
(VSUS)VR3401
(VADR)
VR3601 (VOFS)
100% white signal
(MAIN POWER
Assy)
Adjusting Method
Observe Pin 7 (CBLK) of IC2801, adjust ∆tV shown in Fig. 1 to
150mS ± 20mS, and ∆tH to 1.7mS ± 200nS.
150µs±20µs
tV
C BLK
V blanking
period
Note: When this adjustment is not performed properly, the black
level correction circuit does not operate. The 100% white
signal waveform does not fall towards the black side, and
emission points become inconsistent on the screen.
Adjust TP 7651 so that the DC voltage of point A of the waveform
in Fig. 2 becomes 5V ± 0.1V.
H : 20µs/div V : 2V/div
5V
GND
Note: When this adjustment is not performed properly, the
screen flows slantingly when NTSC signals are input.
1. Connect TP K7503 to TP K7502 (GND).
2. Check the waveform of TP 7655 in Fig. 3, and adjust so that
the frequency becomes 43.0Hz ± 0.5 Hz.
3. Then disconnect the TP K7503 and TP K7502 (GND), and
check that the frequency is 52.5 Hz ± 3 Hz.
H : 2ms/div V : 2V/div
GND
Note: When this adjustment is not performed properly, the
screen moves or flows up and down when NTSC signals
are input.
VSUS (sustain power supply voltage)
Check the drive voltage label value (Note 4), adjust VR3301 so
that value between TP3301 (VSUS) and TP3302 (SUS. GND)
becomes this value.
VADR (address power supply voltage)
Check the drive voltage label value, adjust VR3401 so that value
between TP3401 (VADR) and TP3402 (ADR. GND) becomes
this value.
VOFS (offset power supply voltage)
Check the drive voltage label value, adjust VR3601 so that value
between TP3601 (VOFS) and TP3602 (OFS. GND) becomes
this value.
Note: When the V sus voltage adjustments are not performed
properly, dot-like blinking luminance points appear. If
deviated greatly from the right adjustment, PDP will stop
discharging.
When the VADR and VOFS voltage adjustments are not
performed properly, dot-like blinking luminance points
appear. If deviated greatly from the right adjustment,
these will become white.
10
1.7µs±200µs
tH
C BLK
H blanking
period
Fig. 1
A
Fig. 2
Fig. 3